Ecology can be studied at very large scales: Biosphere

















What makes up the BIOSPHERE?

Energy and water exist and move around the biosphere in different forms/states

Where does energy come from?



















“A thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community. It is wrong when it tends otherwise” -Aldo Leopold

Painting Chalon Sombrero mountain in Peru

Albedo

Global albedo is highly variable in time and place

Albedo positive feedbacks and Snowball Earth

Earth’s average albedo is ~0.3, keeping surface @ 15°C

Do you think global albedo is stable?

Albedo: cold generates cold but…..

Sun is the Earth’s primary form of heat energy, via radiation



  • ~1/3 of sunlight energy reflects back to space


  • Rest is absorbed by land, ocean and atmosphere


  • Exact amount absorbed depends on both surface and atmosphere
    • major contributor of the Earth Energy Budget



  • The balance of incoming and outgoing radiation makes up the Earth Energy Budget

Why clouds are cool…

Composition of the atmosphere alters the greenhouse effect



  • Gases have different RESIDENCE TIMES
    • N2 = 13 million years (inert)
    • O2 = 10,000 years (inert)
    • N20 = 114 years
    • CH4 (methane) = 12 years
    • CO2 = 5-200 years (1/2 removed quickly)



  • Water vapor is reactive and highly variable
    • 10 day residence time
    • seasonally and spatially

Greenhouse gas absorption spectra for outgoing radiation


Changes in composition impact atmospheric heating

Water vapor is the most abundant greenhouse gas



  • NASA recently confirmed heat-trapping effect of water vapor in the atmosphere
    • critical component of climate change
    • collects at tropical latitudes


  • 2x climate warming caused by increased CO2


  • Difficult to quantify
    • residence time in days
    • consider cloud variability

Solar energy & water cycle connected

Water cycle = movement of water within the earth and atmosphere




















25% of incoming solar energy leaves the surface through evaporation

Evapotranspiration: Energetics of water movement

Water enters the atmosphere as vapor from surfaces (evaporation) and from leaves (transpiration)

  • Water has high specific heat
    • 4x more energy to heat water than air
    • absorbs/holds solar energy well


  • 30% of oceans evaporate per year
  • >60% of rainfall is lost to evapotranspiration


  • Large energy fluxes when water changes state
    • evapotranspiration cools surfaces
    • condensation warms atmosphere

Global water cycle: 577,000 km3 of water circulates each year

Global net movement as precipitation ≠ evapotranspiration

Global water cycle: Residence times matter for availability

Water is exists in different ‘storage pools’ for variable amounts of time

Fresh water for humans….